The Quest for RGB

The Quest for RGB

        During a Saturday in early May 2018 this summer, I was over in the Squirrel Hill area of Pittsburgh in order to stop by to the nearest Get Go for cheaper gasoline for the car. While in that area, I noticed an estate sale going on. Considering estate, garage, yard, and flea market sales have the potential to sell awesome vintage stuff (such as retro video games and vintage technology) for cheap, I decided to stop by and check it out. I'm glad I did stop by; I found treasure that day!

   The estate sale seemed to belong to an older, classy Italian who recently passed away, who had some high-end, retro, AV equipment. The item that caught my eye the most was an old Sony CRT monitor, with a listed sales price of an incredibly affordable $20. Although I've never seen this particular model of CRT before and didn't know exactly what it was at first, it did look quite high-end, and I did notice a "Digital RGB" indicator and a "Sony Trinitron" logo on the front. Apparently this model of CRT could support RGB input, which is the highest quality video that retro video game consoles can output! Although I already had an older CRT which is starting to go bad, I decided to take the risk and purchase it. Also purchased with the lot was a VK-2D Multi-Input Cable for the CRT, and a generic 3.5mm to Component jack cable. This was the 2nd and final day of the Estate sale, so everything was being sold for half-off. (I didn't realize this until after the purchase; otherwise, I would have also purchased the remote and TV tuner that was compatible with the CRT).

 

   The CRT was huge, and weighed about 120 pounds, so a helper at the estate sale and I had to do a two-person lift to haul this treasure into the car. Back at the apartment, I did some research online for what I found. The find was a Sony Profeel KX-2501A Component CRT, which is a high-end CRT manufactured during the 1980s by Sony. It uses a high-end Sony Trinitron monitor, a proprietary Sony technology which reduces the amount of color bleed between pixels. It is known as a "component TV", not because it has component AV inputs (YPbPr), but because it requires external hardware ("components") to fully utilize it. For example, the CRT doesn't include built-in speakers; it has speaker jacks to hook up to 8-16Ω stereo speaker equipment. Furthermore, it is best to use the compatible VTX-1000R TV Tuner with it, which allows hooking up multiple RCA and other inputs to the monitor (such as analog TV on RF), as well as hooking all equipment via a single, optional VK-2D 8-pin DIN Multi Input cable. The CRT also is compatible with the retrotacular Remote Commander RM-205 remote.

The Sony KX-2501a

(hooked up to a Sega Saturn via RGB)

   According to the Vintage Knob, the Sony "Profeel" line of CRTs was Sony's marketing term for their consumer and semi-pro product line of CRTs, with the product line positioned slightly below their fully professional product lines. Their professional product lines were their PVM (Professional Video Monitor) and BVM (Broadcast Video Monitors) monitors. These 3 product lines are highly sought out by retro video gaming and video enthusiasts due to their quality. They utilize Sony Trinitron monitors, high quality monitors which are sharp, bright, and clear. You can learn more about why Sony Trinitron monitors were (and still are) the king of CRT technologies in this informative YouTube video.

    Not only do these monitors contain high quality Trinitron monitors, but most of them have inputs for digital RGB. digital RGB is the best quality AV you can get out of most retro video game consoles. Compared to other inferior AV input types (such as RF, Composite, or S-Video), RGB separates the red, green, blue, and sync information on video into separate signals. The other video input types mentioned combine all or some of the color information into individual signals, instead of separating each piece of information into separate signals. This combining of signals causes much signal interference and loss of color quality and information. RGB, on the other hand, separates each piece of color information into their own wire/signal, preventing any interference, and ensuring perfect color accuracy and quality. This is why digital RGB is such a big deal for video enthusiasts. You can learn more about what digital RGB is and why it is so spectacularly awesome for retro video games at this webpage and at the retrorgb.com website.

Comparison between
lowest quality RF
and high-quality RGB video

(Source: RetroRGB website)

Unfortunately, there was a VTX-1000R TV tuner and the remote for the CRT for sale at the estate sale, but I didn't realize I should have picked it up at the time. I later picked up both for relatively cheap on eBay (but not as cheap as at the estate sale). Dumb mistake!

The KX-2501A monitor in action,

with VTX-1000R TV tuner and Remote Commander

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Getting RGB into this monitor

    As previously mentioned, Digital RGB is the best quality AV input for most retro video game consoles. RGB can be input to most high-end CRTs either thru SCART or thru BNC (RGBHV) connections. SCART is a European standard, and uses a 21-pin connector which carries RGB signals. Few if any monitors in North America use SCART inputs; however, many higher end CRTs have BNC connections for RGB (RGBHV or RGBs), which are more common than SCART inputs. SCART contains both audio and video on one cable, while BNC connections use 4-5 BNC connections for video, with audio via left/right RCA connections.

  The Sony Profeel KX-2501A does support RGB input; however; it neither uses SCART or BNC inputs for RGB, and instead, uses a proprietary IDC34 jack, which looks the same as a 34-pin floppy drive jack (see input panel on above picture). This change in input interface was a big problem with getting RGB input on the CRT. After doing some research online, I discovered this blog post from WaveBeam on how to rewire the pins on a SCART jack into such an IDC34 port for transmitting an RGB signal, as well as a proof-of-concept by another person who got RGB working via BNC+RCA connection. Later I discovered a Ben Heck article on creating an AV switcher circuit using Bus Switcher ICs.

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Enter Sony Super Multi (X) RGB Kits

  With the information researched in those links, I have designed the ultimate conversion interface kit for getting RGB input into IDC34 monitors such as mine. The R&D of the products are in late stage development (about 90% complete), and the kits should be ready to be sold to the public at around early October, after pricing, packaging, and an online store are setup.

    The Sony Super Multi RGB product line of kits will contain two kits: The Sony Super Multi RGB, and the Sony Super Multi X RGB. The former kit is the basic kit, while the latter is the premium kit. Both kits will allow one to interface both SCART and BNC (RGBHV/RGBs+RCA stereo audio) RGB AV into their IDC34 port on their monitor, as well as to use either a standard (twisted) IDC34 floppy cable or a nonstandard one. The main difference between the 2 kits is that the former is a passive circuit and does not prohibit the usage of both SCART and BNC inputs active at the same (attempting to use both will mux both signals to the CRT), while the latter is an active, powered, digital circuit that only allows one input type active at the same time. The latter uses an AV Input source switch to select which input to use, power supply, and a few SMT Bus Switcher ICs to fix the design flaw of the standard kit; however, it costs more and is harder to assemble, due to the few SMT components and more complex design. Both kits will come with color instruction manuals for how to use and assemble the kits. The parts used for the AV inputs will be high-quality, non-oriental parts, in order to ensure a pure AV signal. Both kits will be open-sourced, fabricated at OSHPark, and were designed with Autodesk Eagle. Pre-assembled kits will be tested for QA assurance before shipping.

 SSM RGB Kit

SSMX RGB Kit

Manuals

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   Stay tuned for more news about the development of the Sony Super Multi kits, and an eventual release date for the first batch of kits. The source material for the kits and the manuals will be released when the design is finalized and ready to ship. The EagleSoft Ltd website has been updated with a new "Electronics" tab, including a WIP page for the SSM Kits.